Jezero[a] (ICAO: JZRO) is a crater on Mars in the Syrtis Major quadrangle,[3] about 45.0 km (28.0 mi) in diameter.

From a study of the delta and channels, it was concluded that the lake inside the crater probably formed during a period in which there was continual surface runoff.

[5] In 2007, following the discovery of its ancient lake, the crater was named after Jezero, Bosnia and Herzegovina, one of several eponymous towns in the country.

[8] In November 2018, it was announced that Jezero had been chosen as the landing site for the rover Perseverance as part of NASA's Mars 2020 mission.

[19] In a March 2015 paper, researchers from Brown University described how an ancient Martian lake system existed in Jezero.

[23] Since it is believed that the lake was long-lived, life may have developed in the crater; the delta may have required a period of one to ten million years to form.

[28][29] In early 2017 it was selected as one of the top three candidate landing sites, along with northeast Syrtis, 30 km (19 mi) to the southwest.

It is hoped that a later mission could then return Martian samples from sites identified as probably containing remains of life.

[33] On 19 April 2021, Ingenuity performed the first powered flight on Mars from Jezero, which received the commemorative ICAO airport code JZRO.

This design would ease the schedule of the whole project, giving controllers time and flexibility to carry out the required operations.

[37] In addition, NASA may change the solar panels on lander with Radioisotope Thermoelectric Generator, a nuclear power source, to ensure sufficient power and to keep the rocket's propulsion system from getting too cold, thus ensuring a longer lifetime, better thermal protection and safe operation even if they are carried in Mars Global Dust Storm Season, but these changes are still to be clarified by NASA.

Perseverance made these observations mostly with its cameras and a group of sensors in the Mars Environmental Dynamics Analyzer (MEDA).